We propose a new approach to studying the pass-through of credit expansion policies that focuses on frictions, such as asymmetric information, that arise in the interaction between banks and borrowers. We decompose the effect of changes in banks’ cost of funds on aggregate borrowing into the product of banks’ marginal propensity to lend (MPL) to borrowers and those borrowers’ marginal propensity to borrow (MPB), aggregated over all borrowers in the economy. We apply our framework by estimating heterogeneous MPBs and MPLs in the U.S. credit card market. Using panel data on 8.5 million credit cards and 743 credit limit regression discontinuities, we find that the MPB is declining in credit score, falling from 59% for consumers with FICO scores below 660 to essentially zero for consumers with FICO scores above 740. We use a simple model of optimal credit limits to show that a bank’s MPL depends on a small number of parameters that can be estimated using our credit limit discontinuities. For the lowest FICO score consumers, higher credit limits sharply reduce profits from lending, limiting banks’ optimal MPL to these consumers. The negative correlation between MPB and MPL reduces the impact of changes in banks’ cost of funds on aggregate household borrowing, and highlights the importance of frictions in bank-borrower interactions for understanding the pass-through of credit expansions.

We analyze the effectiveness of consumer financial regulation by considering the 2009 Credit Card Accountability Responsibility and Disclosure (CARD) Act. We use a panel data set covering 160 million credit card accounts and a difference-in-differences research design that compares changes in outcomes over time for consumer credit cards, which were subject to the regulations, to changes for small business credit cards, which the law did not cover. We estimate that regulatory limits on credit card fees reduced overall borrowing costs by an annualized 1.6% of average daily balances, with a decline of more than 5.3% for consumers with FICO scores below 660. We find no evidence of an offsetting increase in interest charges or a reduction in the volume of credit. Taken together, we estimate that the CARD Act saved consumers $11.9 billion a year. We also analyze a nudge that disclosed the interest savings from paying off balances in 36 months rather than making minimum payments. We detect a small increase in the share of accounts making the 36-month payment value but no evidence of a change in overall payments.

Using a large, representative sample of high-frequency credit card transactions in the United States, this paper examines the causal effect of sunshine-induced mood on contemporaneous household credit card spending. We document a 0.3 percent increase in credit card spending in response to a one-unit increase in the same-day local abnormal sunshine. The spending response is stronger for consumers with higher credit card debt, lower FICO score, and shorter tenure with the bank. The effect manifests in long-term, durable goods spending, and is not driven by other weather conditions, complementarity between sunshine and consumption, or intentional choice of consumption time. We document similar responses of spending on seasonal and non-seasonal goods and during times with high and low sunshine levels. Finally, the sunshine effect occurs among consumers with various characteristics.

We examine the ability of the government to impact mortgage refinancing activity and spur consumption by focusing on the Home Affordable Refinance Program (HARP) that relaxed housing equity constraints by extending government credit guarantee on insufficiently collateralized refinanced mortgages. Difference-in-difference tests based on program eligibility criteria reveal a significant increase in refinancing activity by HARP. More than three million eligible borrowers with primarily fixed-rate mortgages refinanced under HARP, receiving an average reduction of 1.45% in interest rate ($3,000 in annual savings). Durable spending by borrowers increased significantly after refinancing. Regions more exposed to the program saw a relative increase in non-durable and durable consumer spending, a decline in foreclosure rates, and faster recovery in house prices. Competitive frictions in the refinancing market hampered the program’s impact: the take-up rate and annual savings among those who refinanced were reduced by 10–20%, with amplified effects for the most indebted borrowers.

During the first half of 2020, the difference in savings from mortgage refinancing between high- and low-income borrowers was 10 times higher than before. This was the result of two factors: high-income borrowers increased their refinancing activity more than otherwise comparable low-income borrowers and, conditional on refinancing, they captured slightly larger improvements in interest rates. Refinancing inequality increases with the severity of the COVID-19 pandemic and is characterized by an underrepresentation of low-income borrowers in the pool of applications. We estimate a difference of $5 billion in savings between the top income quintile and the rest of the market.